XXXI. A GENERAL RESUME OF IMMUNITY. 



BY PROFESSOR JULES BORDET. 



THE majority of the articles which my friend and collaborator, 

 Dr. Gay, has been so kind as to translate and bring together in this 

 volume, bear on the general subject of immunity and have all more 

 or less a single trend. The logical connection between these articles 

 will be quite evident to the reader, who will have grasped my 

 general conception of the mechanism of immunity and of the mode 

 of action of sera so far as we can understand them in the present 

 stage of development of science. I may content myself, then, in 

 this final chapter with certain additional explanations. 



I should have been pleased to conclude this volume with a syn- 

 thetic view of the entire subject, or a general theory capable of 

 coordinating the many facts that have been acquired. But in 

 spite of the results that have been obtained by an army of investi- 

 gators for many years, I must admit that such an attempt seems to 

 me at the present day both rash and of questionable value. It is 

 rash, on account of the great gaps that still exist in our knowledge 

 of immunity. In spite of the numerous data which we possess, it is 

 as yet impossible to offer a coherent whole or an harmonious and 

 complete system; many of the facts which we have, cannot, as yet, 

 be classed according either to relations or consequences. Anyone 

 who should attempt at the present day to penetrate the mystery 

 which shrouds the numerous problems of immunity by reasoning 

 alone would be sure to fall into error. Immunity, like other bio- 

 logical sciences, does not permit overgeneralizing and adventurous 

 theories. Immunity is scarcely in a shape to permit profitable 

 deduction, since deduction in its endeavor to penetrate too rapidly 

 and deeply into the unknown, loses immediate contact with estab- 

 lished facts. Are not discoveries frequently unexpected? Do not 

 experimenters find that their researches overthrow expectations 

 which seem quite reasonable, and is it not evident that logic totters 



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